Patch "scsi: lpfc: Add missing memory barrier" has been added to the 4.4-stable tree

Patch "scsi: lpfc: Add missing memory barrier" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    scsi: lpfc: Add missing memory barrier

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-lpfc-add-missing-memory-barrier.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sun Nov 19 12:02:55 CET 2017
From: James Smart <james.smart@broadcom.com>
Date: Mon, 19 Dec 2016 15:07:30 -0800
Subject: scsi: lpfc: Add missing memory barrier

From: James Smart <james.smart@broadcom.com>


[ Upstream commit 6b3b3bdb83b4ad51252d21bb13596db879e51850 ]

On loosely ordered memory systems (PPC for example), the WQE elements
were being updated in memory, but not necessarily flushed before the
separate doorbell was written to hw which would cause hw to dma the
WQE element. Thus, the hardware occasionally received partially
updated WQE data.

Add the memory barrier after updating the WQE memory.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/scsi/lpfc/lpfc_sli.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -118,6 +118,8 @@ lpfc_sli4_wq_put(struct lpfc_queue *q, u
 	if (q->phba->sli3_options & LPFC_SLI4_PHWQ_ENABLED)
 		bf_set(wqe_wqid, &wqe->generic.wqe_com, q->queue_id);
 	lpfc_sli_pcimem_bcopy(wqe, temp_wqe, q->entry_size);
+	/* ensure WQE bcopy flushed before doorbell write */
+	wmb();
 
 	/* Update the host index before invoking device */
 	host_index = q->host_index;


Patches currently in stable-queue which might be from james.smart@broadcom.com are

queue-4.4/scsi-lpfc-clear-the-vendorversion-in-the-plogi-plogi-acc-payload.patch
queue-4.4/scsi-lpfc-correct-host-name-in-symbolic_name-field.patch
queue-4.4/scsi-lpfc-fcoe-vport-enable-disable-does-not-bring-up-the-vport.patch
queue-4.4/scsi-lpfc-correct-issue-leading-to-oops-during-link-reset.patch
queue-4.4/scsi-lpfc-add-missing-memory-barrier.patch